Aerial system for wireless signaling



c. s. FRANKLIN.

AERIAL SYSTEM FOR WIRELESS SIGNALING.

APPLICATION FILED SEPT. 30. 1920.

1,370,735. Patent ed Mar. 8, 1921.

Smvewtoz Charles S. frank/1h @51 mom g 21 W;

UNITED, STATES PATENT OFFICE.

CHARLES SAMUEL FRANKLIN, OE LONDON, ENGLAND, ASSIGNOR TO RADIO CORPO- BATION OF AMERICA, NEW YORK, N. Y., A CORPORATION OF DELAWARE.

' To all whom it may] concern:

, frame and Ihave shown how by'correct phasing of the currents induced in the aerial the polar curves of the single frame and the double frame are superimposed and made to cancel in one direction, whilethey do not cancel in the opposite direction.

The combination provides a system which has a maximum receivin power in one d1- rection in the plane of the system, zero at right angles, and zero in the opposite direction inthe plane of the system, or in any direction desired between this opposite d1- rection and the direction at right angles, but

will not completely cancel'in all directions throughout the 180 degrees at the back of the station at the same time.

The two framesforming the doubleframe I may be combined with the single frame in several ways. They may be tuned independently and combined through mistuned circuits as described in Patent 1,322,101.

By this means the polar curve of the double frame may be varied at will and can be made more nearly identical, both in the horizontal and vertical planes, with one side of the polar curve of the single frame; and by superimposing the two polar curves, as before a more perfect cancellation in all directions at the back of the station is obtained.

I have discovered that while the sensitiveness of such a system depends upon the spacing between the centers of the frames employed, the polar curve is only effected to an extent thereby and it is better the smaller the spacing. By using a receiver of higher magnification therefore such a system may be erected with a small space between the frames comparedwith the wave length and Specification 01 Letters Patent.

AERIAL SYSTEM FOR WIRELESS SIGNALING.

Patented Mar. 8, 1921.

Application filed. September 30, 1920. Serial No. 413,889.

have a better polar curve than a system with a larger space. 1

According to this invention I employ two or more unidirectional systems,as described in specifications of U. S. Patents 1,296,177

and 1,322,101 or modifications of them. I

erect the systems each with a small spacing compared with the wave length at a fraction of a wave length apart one behind the other preferably in the line of the desired commumcation. the aerials of each system are combined by suitable phasing circuits so as to obtain similar polar curves from each system. The resulting currents from eachsystem are then The oscillations resulting in brought by properly arranged wires and arranged to act through additional phasing circuits on a common receiver.

The resulting polar curve for the combined systems is much better than can be obtained from each system by itself. It is sharper in the direction toward the distant transmitting station and gives nearly complete cancellation in all directions, both vertically and horizontally, at the back of the station.

A great many variations and combinations are possible. The aerials employed in each system may be vertical aerials or frame aerials or combinations of these: It is ad vantageous, particularly for duplex work, that each aerial be two frame aerials at right angles to each other connected up to a radiogoniometer. V

The invention is illustrated by way of example in the accompanying drawings in which: I

Figure 1' is a diagram of circuits in accordance with the invention.

l Fig. 2 is the polar curve of reception of one half of the system. V

Fig. 3 is the polar curve of reception of the two halves combined. 1 v

The invention is illustrated in Fig. 1 of the accompanying drawings which figure shows the combination of two systems, each system consisting of two frame aerials spaced a fraction of a wave length apart. In effeet-this is thecombination of two s stems such as described in specification atent 1,322,101.

The four frame aerials A, B, C, D, are erected inthe same vertical plane, and as nearly as is practicable in the line of the desired communication. A and.v B are combined as one system, and C and D as a similar system. AB and CD are then combined together.

The aerials A and B are combined through tuned circuits E and F coupled to them and preferably formed of horizontal wires, properly screened to eliminate all influence except from the aerials, inductance coils at each end and adjustable condensers for tuning. Aerials C and D are similarly combined through the circuits G and H.

The coils I and J of circuits E and F are both coupled to coil M of circuit 0 and the coils K and L of circuits G and H are both coupled to coil N of circuit P.

The circuits 0 and P combine the systems AB and CD and also may consist of properly screened horizontal wires and the necessary tuning elements.

The coils Q and R of the circuits 0 and P are both coupled to a coil S which is connected to a suitable amplifier.

The spacing between the frame aerials A, B, C and D, may be small and is only limited by the degree of amplification practically attainable. Good results have so far been obtained down to one thirtieth of the wave length. For illustration I assume the spacing between A, B, C and D, to be one twentyfourth of the wave length.

Assuming A, B, C and D, tuned to the wave to be received or all equally mistuned, then waves coming from direction AD or DA will produce oscillations in A and B which are 15 degrees out of phase. These oscillations will produce oscillations in circuits E and F which will also be 15 degrees out of phase. The circuit 0 will therefore be acted on by two oscillations having a phase difference of 15 degrees, which can be made a phase difference of 165 degrees by reversing the connections of one of the circuits E or F. If circuit E is mistuned so as to advance the phase of the induced oscilla tions 7idegrees and circuit F mistuned so as to retard the phase of the induced oscillations 7% de rees, then waves coming from the direction DA will produce oscillations in E and F of exactly opposite phase, and no current will result therefrom in circuit 0 if the couplings are correctly adjusted; while waves coming from direction AB will produce oscillations in E and F which are 30 degrees out of phase and will therefore produce oscillations in circuit 0.

Similar adjustments are made in circuits G and H so that waves coming from direction DC produce no current in circuit P.

The polar curve given by each of the systems AB and CD is shown in Fig. 2.

This curve shows two loops toward the back of the station which have a maximum at 120 degrees from the direction AD; as

the distance between the centers of the systems AB and CD is one twelfth wave length,

waves arriving from this direction will produce oscillations in circuits 0 and P which are 15 degrees out of phase, and by reversing the connection of one circuit can be made 165 degrees out of phase. If therefore circuit 0 is mistuned so as to advance the phase of the induced oscillations 7% degrees and circuit P mistuned so as to retard the phase 7% degrees, then waves arriving from this direction 120 degrees from AD will produce oscillations in circuits 0 and P of exactly opposite phase and if the couplings are correctly adjusted will produce no effect on the coil S and the amplifier.

The combined systems will therefore receive best from the direction AD and will give zero reception from directions 90 degrees, 120 degrees and 180 degrees from AD.

The polar curve for the combined systems in the horizontal plane is shown in Fig. 3. The curve shows that a great advantage is gained by combining two systems as described. The maximum receiving power of the system in any direction at the back of the station is only 1.65 9 of the receiving power in the direction AD.

By employing two frame aerials at right angles connected to radiogoniometers in place of each of the single frames, and by suitable phasing, the system can be given zero receiving power in six directions which are controllable.

The method of phasing by mistuning the connecting circuits as described above is very convenient; particularly for damped waves. This method is not essential to the system. For continuous wave reception especially any of the well known phase shifting devices may be employed.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. The combination of a plurality of aerials effectively separated a fraction of a wave length. means for combin ng said aerials to secure a plurality of directiona systems. the aerials comprisingeach system being effectively separateda fraction of a wave length and means for combining the systems to produce increased directivity for the combined systems.

2. The comb nation of a plurality of aerials effectively separated a fraction of a wa e length, means for combining said aerials into a plurality of directional systems, the aerials comprising each system being effectively separated a fraction of a wave length and the systems also being effectively separated a fraction of a wave length and means for combining the systems.

3. The combination of a plurality of aerials efiectively separated a fraction of a wave length, means for combining said length, a common receiver for the systems and circuits for coupling the systems to said receiver.

4. The combination of a plurality of directional aerials effectively separated a fraction of a wave length, means for combining successive aerials to secure a plurality of directional systems and means forcombining the systems.

5. The combination of a plurality of aerials effectively separated a fraction of a wave length, means for combining a plurality oi successive aerials to secure a plurality of systems, said systems being effectively separated a fraction of a wave length and means for combining the systems.

6. The combination of a plurality of directional aerials effectively separated a fraction of a wave length, means for combining said aerials to secure a plurality of systems of greater directivity, the aerials comprising each system being efl'ectively separated a fraction of a wave length and means for combining the systems to produce further increased directivity. v

7 The combination of two aerial systems effectively separated a fraction of a wave length, each system comprising two directional aerials effectively separated a fraction of a wave length and means for combining the aerials of each system to produce increased directivity, and means for combiningthe systems to produce further increased directivity.

8. The combination of a plurality of similar aerial systems eiiectively separated a fractionof a wave length, each system comprising a plurality of directional aerials also e'il'ectively separated a fraction of a wave length, means for combining the aerials of each system to produce increased directivity and means for combining the systems to produce greater directivity for the combined systems.

9. The combination of two similar aerial systems effectively separated a fraction of a wave length, each system comprising two directional aerials effectively separated a fraction of a wave length, means for combining the aerials of each system to produce increased directivity, and means for combining the systems to produce a greater directivity for'the combined systems.

10. The combination of a plurality of aerials spaced apart in respect to the general direction of desired communication, an intermediate circuit coupled to each aerial, a plurality of connecting circuits coupling adjacent intermediate circuits together in sets, and a detector circuit coupled to the connecting circuits.

11. The combination of a plurality of aerials spaced apart in respect to the general direction of desired communication, an intermediate circuit coupled to each aerial, a plurality of connectin circuits coupling adjacent intermediate circuits together in pairs, and a detector circuit coupled to the connecting circuits.

12. The combination set forth in claim 10 in which intermediate circuits of each set are adjusted so that the oscillations therein are in phase.

13. The combination set forth in claim 10 in. which the intermediate circuits of each set are adjusted so that the oscillations therein are in phase and the connecting circuits are adjusted so that the oscillations therein are also in phase.

14. The combination of four aerials equally spaced in the direction of waves to be received, an intermediate circuit coupled to each aerial,two circuits, one coupled to the first and second intermediate circuits and the other coupled to the third and fourth intermediate circuits and a single circuit coupled to'the two circuits.

15. The combination set forth in claim 14 in which the first and second intermediate circuits are equally mistuned in opposite senses and the third and fourth are similarly mistuned.

CHARLES. SAMUEL FRANKLIN. 

